Research On K Type Constituent Viscoelastic Medium And Its Characteristic Of Wave Field

This paper relies on my tutor's Natural Science Fund Project: the nature gas and hydrate research on the basic of the composition elastic porous media (No: 40474043). This paper is focus on the study of the numerical modeling of the seismic wave field and the theory of the viscoelastic composition medium. Although homogeneous isotropic elastic media and seismic wave propagation theory can simulate the practical media, it would be very difficult to describe the complex physics phenomena of the seismic waves transmission in the stratum full of oil and gas if people use the theory of rock elasticity and wave transmission based on the elastic isotropic single-phase medium because of the viscoelastic, anisotropic and multiphase. This paper base on the practical application, we put forward the viscoelastic porous media theory and use stagger-grid difference method simulating the propagation of seismic wave. It is very useful to the practical application.With my supervisor's guidance and the help of the formal scientific inheritance, the main research as follows:1. Simply describes the Biot theory, the theory of the composition porous media and the developing history and present situation about wave field numerical modeling.2. Mainly describes the Kelvin media model and composition viscoelastic media model. This paper put forward the composition viscoelastic model base on Kelvin media model. Set up elastic matrix and elastic model, also set up the composition viscoelastic seismic wave equation.3. Research the phase function and amplitude function of composition viscoelastic media. Set up the equation of phase velocity and attenuation parameter and quality gene. Draw the correlation graph by matlab, and analyze the graph by contrast. we research the variety rule of the parameter which referred above with the change of phi.4. Set up the difference equation of elastic media, Kelvin media and composition viscoelastic media. Then programming by matlab implements the numerical modeling of seismic wave in the two-phase composition viscoelastic porous media model. simulates snapshots and synthetic seismograms in various theoretical geologic models, analyses and explains compressional wave, shear wave. Mainly analyze the characteristic of amplitude spectrum of compressional wave and shear wave in the same geology model. Separate analyze the attenuation and difference of amplitude of the compressional wave and shear wave, which is different distance from the source. This paper proves composition viscoelastic model is feasible. It is superior to Kelvin media model, because it is optional and applicable. The researches can be expanded to exploration and development fields of oil, natural gas and water resource etc. which have great theoretical and practical significance for people to understand wave propagation rules in viscoelastic porous media and represent underground media constitution and lithology characteristic.